Plug for ingot molds



Feb. 11, 1941. H. K. RIGDON PLUG FOR INGOT MOLDS Fi led Oct. 5. 1939 INVENTOR. BY l-loward K. Rigdon 5W,M AM

ATTORNEYS.

Patented. Feb. 11,

UNITED STATES PATENT OFFICE 2,231,774 v PLUG r'ox INGOTMOLDS Howard K. Rigdom'lainesfille, omo, assignor to Hill Burgwin, Pittsburgh, Pa as trustee Application October 3, 1939, Serial No. 297,719-

3 Claims. (Cl. 22-148) This invention is an improved plug for the downwardly convergent bottom openings of ingot molds of the big-end-up variety commonly used for casting steel ingots.

5 Inasmuch as a plug is ordinarily good for only one pouring, cheapness is the greatest desideratum aside from the efiectivenes's of the plug in serving its intended purpose. Heretofore, relativelyinexpensive plugs of refractory material have been used, but these have proven to be unsatisfactory because of breakage, and more particularly because particles of the material, or gas bubbles resulting from contact of the molten metal with the material, frequently rise into the body of molten metal during the teeming of the ingot resulting in' so-called inclusions" in the ingot, and blow-holes or weak spots in the steel .plates or strips subsequently rolled therefrom. Solid cast iron plugs are free from the above objections, but are expensive. Attempts have been made to retain the virtue of the cast iron plug and reduce the cost by applying a stamped or sheared metal plate to the top of a body of refractory material and securing it thereto by a bolt or similar means, thereby to produce a composite plug which fits entirely within and closes the bottom opening of the mold. Such a plug, provided the stamped or sheared plate is free from burrs, gives very satisfactory results, but by reason of its construction is relatively expe sive. The general purpose of my invention is to produce a plug composed-of a metal top upon which the molten metal is adapted to impinge during I the pouring of an ingot, and a non-metallic body engaged with and attached to the underside of said top and which is of a. material that will char and become friable under the intense heat. leaving a residue in the nature of charcoal. A ma-. terial suitable for the purpose is a mixture of sawdust and an appropriate binder, such as a proper kind of glue or other substance that will evaporate when subjectedto high temperature. The advantage of such a compound lies in the 5 fact that when an ingot, with the composite plug adhering to thebottom thereof as usual, is lowered into a soaking pit pursuant to common practice, the charredbody portion of the plug will disintegrate and the particles thereof mingle with 50 the coke customarily present in the bottom of the soaking pit as a conformablesupport for the ingot. As a consequence of thesimilarlty of the material of the plug body and the coke bed-the so-called sloppy bottom" condition of the pit,

. 55 resulting from mixing refractory material with the coke, is'avoided and much'difficulty and'annoyance in frequent cleaning of the pit and in- I gots necessitated by such condition is obviated.

The purpose aforesaid is attained'in the embodiments of the invention illustrated in the ac- 5 companying drawing wherein Fig. 1 is a perspective view, and Fig. 2 a central vertical section, through a mold plug constructed in accordance with the invention; Fig. 3 is a central vertical section through the lower portion of an ini0 got mold showing myimproved plug in place within the bottom opening thereof, and indicating, in dot and-dash lines, an implement or hook by which the plug is lowered'into place; Figs.

illustrative of one way of fabricating the plug. 25

In each'of the several forms of the invention shown in the drawing, the metal top, or metallic top casting, is designated I, and the non-metallic bottom casting is designated 2. While I have previously set out herein the desirability 30 of a material for the non-metallic bottom casting 'that would char and become friable under intense heat, and have specified a mixture of sawdust and a suitable'volatile binder as one compound adapted to the purpose, it will be under- 35 stood that various ingredients may be combined in the production of the non-metallic casting, many well known non-mineral materials and binders being suitable.

The anchorage means by which the .two cast- 40 ings are connected together is designated, generally, by the numeral 3. In the form of the invention illustrated in Fig. '7, the anchorage means 3 may consist of nails or pieces of wire orthe like, desirably bent so as to enhance their hold in the castings. In the other forms of the invention herein illustrated, handling means through which the plugs may be supported by a suitable implement or hook, is constituted of a part of the anchorage means.

- In the embodiment illustrated in Figs. 1 to 3, Y the handling means. a is constituted of the central portion of an inverted U-shaped .rod or wire that forms the anchorage element 3. The ends of the element are embedded within the nonmetallic casting 2 and are shown as upset to provide abutments or heads b.

In Fig. 4, the anchorage means 3 is in the form of a split or open sided ring whose central portion constitutes the handling means a, and whose ends are embedded in the non-metallic casting. In Fig. 5, the anchorage means 3, including the handling means a, is in the form of a staple constructed of a piece of wire or rod of suitable diameter whose ends are turned inwardly at c to provide abutments that enhance the hold of the anchorage means within the non-metallic body. In Fig. 6, the anchorage means 3 consists of a double ended hook, desirably S-shaped, one end of which, designated d, is embedded in the non-metallic casting, while the opposite end provides the handling means a.

The method of producing the plug contemplates, broadly, preforming one casting with the anchorage means partly embedded therein and projecting from the side thereof to which the other casting is to be applied; and then applying to such side the material of the other casting while in mobile condition. In accordance with the present preferred method, the non-metallic casting 2 is molded with the lower portion of the anchorage means 3 embedded therein andwith the upper portion of said means projecting well above the top surface thereof. The casting may be formed 'in a cavity 5 of a mold -6, conventionally illustrated in Fig. 8, or such casting, previously molded, may be placed within the cavity. Molten metal is then poured upon the non-metallic casting, in some such manner as that illustrated in Fig. 8, to provide the casting I within which is encased the protruding portion or portions of the anchorage means. In the forms of the invention incorporating the handling means a, the appropriately shaped upper ends of the anchorage means extend well above the top surface of the casting I.

By engaging the hooked lower end of an implement 8, shown in dot-and-dash lines in Fig. 3, with the handling means a, which, in the forms shown, is in the nature of an eye, the plug may, by means of said implement, be very conveniently lowered into the bottom opening 0 of the mold M, Fig. 3. The fact that the handling means is substantially central of the plug insures proper entrance of the plug into the opening.

Notwithstanding the cheapness and simplicity of my improved mold plug, it is highly eflicient as a closure for the bottom opening of the ingot tom opening of an ingot mold, the same being of a size and shape to fit within and close said opening and comprising'a metallic element that constitutes the upper portion of the plug and against the top side of which the molten metal is adapted to impinge in the pouring of an ingot, and a solid, non-mineral body that constitutes the lower portion of the plug and is connected to the bottom side of said metallic element, the material of said body being such as will char and become friable under intense heat.

2. A plug for the downwardly convergent bottom opening of an ingot mold, the same being of a size and shape to fit within and close said opening and comprising a metallic element that constitutes the upper portion of the plug and against the top side of which the molten metal is adapted to impinge in the pouring of an ingot, and a body that constitutes the lower portion of the plug and is of cellulosic material, the same being connected to the under side of said metallic element.

3. A plug for the downwardly convergent bottom opening of an ingot mold, the same being of a size and shape to fit within and close said opening and comprising a metallic element that constitutes the upper portion of the plug and against the top side of which the molten metal is adapted to impinge in the pouring of an ingot, and a body that constitutes the lower portion of the plug and is attached to the bottom side of the metallic casting, the same being composed of wood sawdust and a suitable volatile binder.

' HOWARD K. RIGDON. 

